Department of Computer Science | Institute of Theoretical Computer Science | CADMO

Theory of Combinatorial Algorithms

Prof. Emo Welzl and Prof. Bernd Gärtner

Mittagsseminar (in cooperation with M. Ghaffari, A. Steger and B. Sudakov)

Mittagsseminar Talk Information

Date and Time: Tuesday, December 15, 2015, 12:15 pm

Duration: 30 minutes

Location: CAB G51

Speaker: Emo Welzl

Embracing Triangles and Simplices

A triple of points in the plane forms an embracing triangle if the origin lies in its convex hull; correspondingly, d+1 points in d-space form an embracing simplex if their convex hull contains the origin. Via Gale duality, the set of embracing simplices of a set S of points is in correspondence to the facets of some simplicial polytope, assuming that S forms with the origin a set in general position.
We discuss the complexity of counting the number of embracing simplices in a set S, starting with a simple formula for embracing triangles. As a by-product we can count the number of facets of the convex hull of n points in general position in d-space orders of magnitude faster than the number of these facets, provided n-d is constant. (Joint work with Alexander Pilz and Manuel Wettstein)

Upcoming talks     |     All previous talks     |     Talks by speaker     |     Upcoming talks in iCal format (beta version!)

Previous talks by year:   2018  2017  2016  2015  2014  2013  2012  2011  2010  2009  2008  2007  2006  2005  2004  2003  2002  2001  2000  1999  1998  1997  1996  

Information for students and suggested topics for student talks

Automatic MiSe System Software Version 1.4803M   |   admin login